Effect of multiple sclerosis serum on ventral root responses in isolated frog spinal cord.

Serum from patients with multiple sclerosis (MS) and other diseases was added to the medium perfusing isolated hemisected frog spinal cord, and the effect on ventral root responses (VRR) tested. As control, a standardized commercial human serum (Moni-trol I) was used. In 25 out of 40 spinal cord preparations Moni-trol gave inhibition of VRR ranging from 2.8 to 23.1%. 76% of the tests with confirmed MS sera showed inhibition of VRR, after deduction of the control serum effect, while 53% of the tests with sera from other diseases were inhibitory. Sera from cases of suspected but clinically unconfirmed MS gave strong inhibition (above 20%).